Dash-pot



G. A. BURNHAM. Y

DASH POT.

APPLICATION FILED AUG.2, 1918.

1,364,980. Patented Jan. 11,1921.

UNITED STATES,

PATENT OFFICE.

GEORGE A. BURNHAM, 0F SAU GUS, MASSACHUSETTS;ASSIGNOR TO SEARS B.

CONDIT, JR., OF BROOKLINE, MASSACHUSETTS. i

DASH-POT.

Specification of Letters Patent.

' Application filed August 2, 1918. Serial No. 247,978J

type in which a flexiblediaphragm iscm-.

member of the time ployed as the movable element. 1 One of the principal ditticultles experienced in the practical operation of such relays is, that the diaphragm soon loses much of itsfiexibility, or; at least itsflexibility is so altered that the time element of the relay is considerably changed from its initial adjustment,- with the result that the best protection is no longer obtained for the circuit controlled by the relay.

The partial loss of flexibility of the diaphragmis due to the drying of the oil hat-- urally contained therein or with which it is treated, with the result that the diaphragm.

becomes relatively stiff, or hard in spots, both of which conditions "serveto operation of the relay.

In practice an attempt ismade to remedy this defect by the frequent oiling or lubrication of the diaphragms by an attendant to maintain them in their condition of maximum flexibility. This treatment, however, is unsatisfactory, for the periods between oilings are uncertain and may be long, and between each oiling, the diaphra m may become partially dryand so alter the time element of the relay.

The object of my invention is in the provision of means, associated with the flexible diaphragm of a dash pot, whereby the diaphragm may be continually maintained moist With oil or other suitable lubricant and therefore in itscondition of maximum flexibility and the relay maintain a constant time element.

The means whereby I accomplish the object of my invention is in the provision of a bath of lubricant in which the diaphragm is in substantially constant communication whereby it may be continually moist and flexible.

The bath .or supply of lubricant may be so arranged with respect to the diaphragm that BURNHAM,

aifect the the-diaphragm is in direct contact there- Patented Jan. 11, 1921. V

with, or the bathof lubricant may be at some convenient point and fluid conducting means, such as wicks, extended therefrom to the diaphragm for the lubrication thereof.

Figure l is asectional elevation of a time limit relay embodying my invention.

Fig; 2 is a sidcelevation of the relay of Fig. I

Fig. 3 is a sectional detail of the dash pot in an operated positionof the diaphragm.

. As here shown. the relay with whichmy invent1on is associated may include the solenoid 1O inclosed in the 'protectingcasing 11 of'ma'gnetic material and forming part of the magnetic circuit ofthe solenoid.

A core 13 comprising the movable-element of thesolenoid is adjustably arranged withinthe solenoid in a tube 14 of non-- magnetic material whereby the current value at which the relay is eiiectively energized may be; adjusted.

said tube 14- and extends above the solenoid and its casing and bears, near its upper end.

a flange 16; A. stem 17 forming apart of the movable member of the time element of the stem and bears against the end ofsaid recess and thefiangelo' of said rod and forms a yielding connection betweensaid rodand- A rod 15 is secured to the upper end of stem and through whicha movement of said 7 rod is communicated to said stem to cans a movement of the latter.

An oil receptacle 20, hereinafter to be 1 more fully described,is secured to the upper end of said stem and has its bottom wall 21 dished to form a piston for the flexible diaphragm of the time element of the relay.

The time element of the relay comprises a dash pot 22 secured by means of a standard 23 above the solenoid of the relay. Said dash pot is formed with a cup-shaped lower face over which the flexible diaphragm is extended and which is secured to said dash pot by the spring rings 26. Said diaphragm is secured'to the stem 17 and the piston at its middle point.

The dash pot 22 of the time element is provided with aleak valve 22 of common construction, by which the time period of the relay may be adjusted, and it is also provided with a valve 31 which serves as a check valve to admit air between the pot and the diaphragm upon a return movement of the diaphragm to permit the rapid recovery of the relay in readiness for a second operation.

Contact members 35 carried by the stem 17 are adapted to engage contact members 36 supported from the solenoid casing for the control of a circuit connected thereto.

The oil receptacle,as previously stated,has its bottom wall dished substantially to conform to the cupped face of the pot 22 and into which it is adapted to press the flexible diaphragm 25 when moved upward by the movable element of the solenoid. The side walls of said receptacle are adapted to extend upward to partially inclose the flexible diaphragm and the dash pot when the relay is in an inoperative position and a bath or supply of oil or other lubricant, indicated at 4L0, is adapted to be contained therein, the level of said bath of oil being preferably at such a height in the oil receptacle that the middle part of the diaphragm is in continual cont-act therewith. By such continual contact, the oil or other lubricant may spread by capillary action over the entire surface and continually maintain the diaphragm lubricated and in a condition of maximum flexibility. With such continual lubrication, the time period of the relay is also maintained constant.

As the piston is moved upward to force the diaphragm within the dash pot upon an operation of the relay, substantially the en tire surface of the diaphragm is progressively brought into contact with the bath or supply of oil and therefore additionally lubricated over its normal lubrication by capillary action.

The walls of the oil receptacle are extended upwardly above the flexible diaphragm sufficiently to prevent the overflow of oil during the upward movement of the piston.

I prefer to have the diaphragm in continual communication with the oil or other lubricant although obviously it may be lubricated only at each operation of the dash pot whereby said diaphragm is always in a condition of maximum flexibility regardless of the more or less extended period of time that may elapse between succeeding operations of the relay and in which period of time the diaphragm may otherwise become dry or sufliciently partially so to change the timeperiod of operation.

It is obvious that my invention may be modified to adapt it for various requirements without departing from the spirit thereof.

I claim 1. A dash-pot having a rigid end-wall, a flexible diaphragm secured thereto, and an actuating piston therefor having an oil-containing portion arranged to contain oil in contact with said diaphragm.

2. A dash-pot having a rigid end-wall, a flexible diaphragm secured thereto, and an actuating piston therefor having its peripheral portion up-turned to form an oilcontainer in which said flexible diaphragm extends adapted to contain oil in contact with said diaphragm.

3. A dash-pot having a rigid end-wall, a flexible diaphragm secured thereto, a movable piston secured to said diaphragm, and an oil receptacle carried by said piston into which said flexible diaphragm extends adapted to contain oil in contact with said diaphragm. i

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing witnesses.

T. T. GREENWOOD, H. B. DAVIS. 

